I was plotting to buy one of these digital audio recorders for journalists, which I want to use for field recordings.
Are these devices good for it?
If i understood your question right you want to record nature sounds?
For this use i would recommend the Zoom H2n.
It is a very sensitiv mobile recorder. Have a look at it.
The question I would ask is for what application? What is it you want to record?? - I have used quite a few of these (from the older style where you had a small micro-cassette to the more modern digital style) and if you are recording voice only they can be helpful. I used these as a paperless way to take notes, record information after exiting sales meetings etc and reviewed these at the end of the day as a way to keep track of details etc. One consideration is that the built in microphones do not have a wide field so you really have to be near the subject / person to get really clear recordings, although I have used them to some success recording lectures, but only if the subject was using a mic/pa. Hope this was helpful to you.